A thin film transistor liquid crystal display (TFT-LCD) controls penetration of light by using optical anisotropy and birefringent characteristic of liquid crystal molecules through a TFT switch and input of signal voltage so as to display images. In a liquid crystal display panel, a color filter substrate and a TFT substrate are boxed together through sealant, and a photo spacer is supported between the two substrates to form a certain cell gap, so that a liquid crystal filling space for filling liquid crystal is formed between the two substrates. The arrangement direction of the liquid crystal molecules in the liquid crystal filling space will be changed under the influence of an external electric field, so as to control the quantity of light passing through the color filter substrate. A liquid crystal module indicates a finished product formed after a back light unit is assembled on the liquid crystal display panel.
When the liquid crystal filling quantity in the liquid crystal display panel is insufficient, or in the presence of air generated during filling and other reasons, after the liquid crystal display panel is boxed, liquid crystal bubbles possibly appear and thus cause abnormity of a product. The present detecting methods include: (1) flapping the surface of the liquid crystal display panel by hands to determine whether liquid crystal bubbles appear in the product; (2) pressing each position of the surface of the liquid crystal display panel by using a pressing bar to determine whether liquid crystal bubbles appear in the product; and (3) dropping a steel ball along a cylindrical steel tube from a certain fixed height to collide with the surface of the liquid crystal display panel, so as to determine whether liquid crystal bubbles appear in the product. All of these detecting methods are single-point static determining methods, and it is difficult to indicate the overall condition of the liquid crystal display panel. If the overall condition of the liquid crystal display panel needs to be indicated, then multiple times of detection are needed at multiple positions of the liquid crystal display panel. The operation thereof is obviously tedious.